I've seen four episodes so far (and eagerly await the final two). As of November 2nd, they are:
"Paradise Lost" "Russian Roulette" "Motel Murder" "No One Could Hear Her Scream"
This story is complex but extremely well told so that viewers can follow all the loose ends. The series focuses on each incident where a young woman or two women (in pairs) vanished and turned up murdered. You get background on the victims and the era, witness statements, existing evidence, and absolutely wonderful original film footage from the 70s, including clips from actual news broadcasts.
Real detectives (some retired) and a newspaper writer appear as they actual work to solve the crimes. The most likely suspect, who confessed in detail and then recanted, is interviewed and his puzzling and sometimes chilling comments are inserted at relevant times. A complicated story, yes, but so well organized that one can easily follow it and be completely drawn in as the mystery unfolds.
This is the real thing. So many crime documentaries lately have become poorly acted soap opera with ghastly made-up dialogue. So it's delightful to see a program like The Eleven! It is mysterious, fascinating, addictive and, most importantly, honest.